purpose : to present the clinical features, biomechanical properties and management of a patient who developed unilateral corneal ectasia after photorefractive keratectomy (prk) case report : the patient was a 24-year-old man without any obvious preoperative risk factor for ectasia who underwent bilateral prk. four years after keratorefractive surgery, the patient presented with loss of visual ...

PURPOSE To quantify optical and biomechanical properties of the feline cornea before and after photorefractive keratectomy (PRK) and assess the relative contribution of different biological factors to refractive outcome. SETTING Department of Ophthalmology, University of Rochester, Rochester, New York, USA. METHODS Adult cats had 6.0 diopter (D) myopic or 4.0 D hyperopic PRK over 6.0 or 8.0...

PURPOSE To compare the effect of Homatropine and Diclofenac eye drops for reducing pain after photorefractive keratectomy (PRK). METHODS This randomized, double-masked, interventional study included 32 patients (64 eyes) who underwent bilateral PRK. After operation, patients received Homatropine eye drops in one eye and Diclofenac eye drops in the fellow eye for 48 h. The level of pain was ev...

OBJECTIVE To evaluate the results of photorefractive keratectomy (PRK) with mitomycin C in myopia correction after five years. METHODS This is a cross sectional study which included 145 eyes of 74 patients in 18 to 51 years age group that were undergoing Photorefractive keratectomy with mitomycin C using Allegretto Wave Eye-Q 400-Hz excimer laser platform in Markazi Eye Center, Tehran, Iran. ...

PURPOSE To determine whether the nerve fiber analyzer GDx with the new variable corneal compensation (VCC) device allows measurements of retinal nerve fiber layer parameters independent from birefringence changes of the cornea after photorefractive keratectomy (PRK). METHODS Retinal nerve fiber layers of 32 eyes in 32 myopic patients undergoing PRK were analyzed using the GDx-VCC. Photorefrac...

BACKGROUND The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight(®) Allegretto platforms. METHODS In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy ...

with the increasing number of keratorefractive surgical procedures in the past years, an increasing number of cataract operations in eyes with previous keratorefractive surgery is anticipated. although cataract extraction seems to be feasible without major technical obstacles, intraocular lens (iol) power calculation remains problematic. insertion of measured k-readings after myopic photorefrac...

BACKGROUND To compare the average values of the American Society of Cataract and Refractive Surgery (ASCRS) and Ocular MD intraocular lens (IOL) calculators to assess their accuracy in predicting IOL power in patients with prior laser-in-situ keratomileusis (LASIK) or photorefractive keratectomy. METHODS In this retrospective study, data from 21 eyes with previous LASIK or photorefractive ker...

We study the possibility of self-trapping of an optical beam in a photorefractive medium under the combined influence of diffraction and self-scattering (two-wave mixing) of its spatial frequency components. We investigate the spectrum of solutions for the resulting photorefractive spatial solitons and discuss their unique properties. Design considerations and material requirements for experime...

Abstract—A physical model for guiding the wave in photorefractive media is studied. Propagation of cos-Gaussian beam as the special cases of sinusoidal-Gaussian beams in photorefractive crystal is simulated numerically by the Crank-Nicolson method in one dimension. Results show that the beam profile deforms as the energy transfers from the center to the tails under propagation. This simulation ...